Counting numbers of n digits that are monotone | C # program to count numbers of n digits that are monotone . ; Considering all possible digits as { 1 , 2 , 3 , . .9 } ; DP [ i ] [ j ] is going to store monotone numbers of length i + 1 considering j + 1 digits . ; Unit length numbers ; Single digit numbers ; Filling rest of the entries in bottom up manner . ; Driver code .
using System ; class GFG { static int DP_s = 9 ; static int getNumMonotone ( int len ) { int [ , ] DP = new int [ len , DP_s ] ; for ( int i = 0 ; i < DP_s ; ++ i ) DP [ 0 , i ] = i + 1 ; for ( int i = 0 ; i < len ; ++ i ) DP [ i , 0 ] = 1 ; for ( int i = 1 ; i < len ; ++ i ) for ( int j = 1 ; j < DP_s ; ++ j ) DP [ i , j ] = DP [ i - 1 , j ] + DP [ i , j - 1 ] ; return DP [ len - 1 , DP_s - 1 ] ; } public static void Main ( ) { Console . WriteLine ( getNumMonotone ( 10 ) ) ; } }